A great number of toys exist that can move in a controlled manner. Traditional toys for example include toy railway sets and toy racing car sets. In such toys, railway tracks or racing tracks are constructed and toy trains or racing cars are guided in circuits by the tracks. The movement of the toy trains or cars, however, is normally only along the fixed track.
Another well-known type of toy is the radio-controlled toy, especially radio-controlled toy cars for example. A radio-controlled toy car can be moved over a surface by a child issuing commands through a radio frequency remote control system.
Also known are toy robots. A toy robot is provided with means for propelling itself over a surface without the direct control of a child. However, if the toy robot is very simple, then the range of movements of the toy robot is limited because without user intervention it will hit obstacles that may damage the toy and will impede its progress. Children will inevitably tend to tire of such toys quite quickly.
A child's interest in a robot-like toy can be increased if the toy is provided with a degree of in-built intelligence such that it can identify obstacles and take evasive action. For example, in principle, a toy robot could be provided with some form of camera and visual recognition system so that obstacles can be identified and evasive action taken. However, this requires quite complicated (and therefore expensive) processing means and such a robot-like toy would be closer to a “real” robot in an industrial and scientific application than a child's toy. The cost would become prohibitive.